TRANSMISSION BELT WHEEL LUG, AND STRUCTURE FOR CONNECTING SAME TO DRIVEN UNIT

Abstract

 A pulley and a structure having the pulley connected with a driven unit are provided. The pulley includes a wheel portion and a lug portion. The wheel portion includes two circular end surfaces opposing each other and a side surface connecting the two end surfaces. The side surface includes a main arc face and a branch arc face. The branch arc face has a head end connected to the main arc face and a tail end configured to connect a strap. The branch arc face has a width in an axial direction of the wheel portion smaller than a width of the main arc face. The branch arc face and the main arc face form a continuous circular arc surface on which the strap rides. The lug portion is fixed to the wheel portion, disposed at a position adjacent to the branch arc face along the width of the main arc face and extends to protrude beyond the branch arc face in a radial direction of the wheel portion. The lug portion is configured to connect the pulley to a driven unit.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the field of connection structure for mechanical transmission units, and particularly to a connection structure between a robotic arm and an end effector of a surgical robot.

BACKGROUND

[0002] The medical microsurgical instrument is widely used in all kinds of surgeries due to its advantages of accurate positioning, stable operation, dexterity, wide working range, fearlessness of radiation and infection, etc. During the operation, a plurality of robotic arms are controlled to move above a patient's body, and then perform the operation through an aperture pre-opened on the skin of the patient's body. The robotic arm is connected to an end effector by steel wires or steel straps, so that an end effector passes through the aperture on the skin of the patient's body and freely rotates around a point at the aperture.

[0003] In general, the strap drive train employs straps and pulleys that are made from stainless steel with extremely high rigidity and compactness. The strap usually connects the pulley through a connector with a certain length. In a typical solution for rotation of the pulley over 90 degrees both clockwise and anticlockwise, as shown in FIG. 2, two steel straps (straps 300) are provided and wrap the pulley 110' in opposite directions. Each of the straps connects the pulley through a connector 301 and then extends to wrap the periphery of the pulley. The two straps run parallelly and offset with respect to each other in a thickness direction of the pulley, so that the two straps wrap the pulley over 90 degrees in opposite directions. Accordingly, the pulley 110' should have a thickness equal to or larger than the sum of the widths of the two straps to avoid overlapping of the two straps and interference between the two straps. The connector 301 is received in a groove 113' recessed from the periphery to avoid between the connector and the internal parts of the robotic arm during rotation of the pulley. It is ensured that the connected 301, when pulled, would not be detached from the pulley 110' during the rotation of the pulley clockwise and anticlockwise over 90 degrees. In general, a larger angle at which the strap 300 wraps the pulley 110' results in larger friction between the strap 300 and the pulley 110' and thus a reduced tension on the strap 301, thereby improving the safety margin.

[0004] Multiple robotic arms may be involved during the operation. Due to a small size of the aperture pre-opened on the skin of the patient's body, it is generally desirable that the robotic arm has a very compact structure and is thin enough to avoid interference between the robotic arms within a limited space. Typically, a joint, which connects the robotic arm and the end effector, includes an inner lug fixed on the end effector. As shown in FIG. 1, the inner lug includes two tabs 120' connecting the end effector (driven unit 200) and the pulley 110'. The pulley 110' is fixed to the tabs 120' which are integrally formed with the driven unit. Thus, the pulley 110' is fixed to the driven unit 200 in such a way that the driven unit 200 is rotated by as much an angle as the pulley 110' is rotated. In this solution, the tabs 120' and the pulley 110' are connected and inserted into an outer lug of the robotic arm. The tabs 120' and the pulley 110' are hinged to the outer lug through a pin, thereby achieving a connection between the end effector and an end of the robotic arm. The end of the robotic arm has a thickness of at least the sum of the thicknesses of the outer lug, the tabs 120' and the pulley 110'. It is difficult to realize both minimizing the thickness of the robotic arm and maximizing the rigidity of the robotic arm and the end effector, and thus tradeoffs between them are desirable.

[0005] Therefore, it is desirable to provide a compact structure in which the pulley and the driven unit are connected.

SUMMARY

[0006] The present disclosure aims to provide a pulley and a structure including the pulley connected with a driven unit to resolve the conflict between the minimization of the thickness and maximization of the rigidity of the connection between the end effector and the robotic arm and thus to achieve both a small thickness and a large rigidity.

[0007] In order to solve the aforementioned problem, embodiments of the present disclosure provide solutions as follows.

[0008] A pulley is provided and includes a wheel portion and a lug portion. The wheel portion includes two circular end surfaces opposing each other and a side surface connecting the two end surfaces. The side surface includes a main arc face and a branch arc face. The branch arc face has a head end connected to the main arc face and a tail end configured to connect a strap. The branch arc face has a width in an axial direction of the wheel portion smaller than a width of the main arc face. The branch arc face and the main arc face form a continuous circular arc surface on which the strap rides. The lug portion is fixed to the wheel portion. The lug portion is disposed at a position adjacent to the branch arc face along the width of the main arc face and extends to protrude beyond the branch arc face in a radial direction of the wheel portion. The lug portion is configured to connect the pulley to a driven unit.

[0009] In an embodiment, the lug portion includes a first end surface adjacent to and perpendicular to the branch arc face, a second end surface opposite to the first end surface, a first side surface connecting the first end surface and the second end surface and extending from the main arc face, a top surface connecting the first end surface and the second end surface and disposed at a top of the pulley, and a second side surface disposed above the branch arc face and connecting the top surface. The top surface is configured to be attached to a surface of the driven unit.

[0010] In an embodiment, a connector chamber is provided at the tail end of the branch arc face and configured to receive and hold a strap connector which is connected to the strap and matched in shape with the connector chamber.

[0011] In an embodiment, the connector chamber includes an abdomen and a mouth sized smaller than the abdomen, and the mouth opens to the branch arc face.

[0012] In an embodiment, the mouth has a top connecting the second side surface, and the top surface is disposed above the connector chamber and spaced from the connector chamber.

[0013] In an embodiment, two branch arc faces and two lug portions are provided, and the pulley is rotated-symmetrical about the radial direction of the wheel portion.

[0014] In an embodiment, each of the two branch arc faces has a central angle larger than 90°.

[0015] In an embodiment, the main arc face has a central angle of 180°, the width of each of the two branch arc faces is half that of the main arc face, the two branch arc faces partly overlap in the axial direction of the wheel portion and share the main arc face.

[0016] In an embodiment, the first side surface of the lug portion transitions smoothly to the main arc face.

[0017] A structure is provided and includes a driven unit and a pulley according to any one of the aforementioned embodiments. The pulley is connected to the driven unit through the lug portion.

[0018] In an embodiment, the driven unit is an end effector for a robotic arm.

[0019] Compared with the related art, in the pulley and the structure including the pulley and the driven unit connected to each other according to the embodiments of the present disclosure, an integrally formed pulley is provided with a simpler structure, in which the wheel portion is improved for wrapping of the strap and an additional lug portion is provided on the wheel portion, the pulley is fixed to the driven unit through the lug portion integrally formed with the wheel portion, so that components such as the tabs of the inner lug employed in the existing technology can be omitted. In this way, the thickness of the connection of the pulley is reduced, and a compact structure including the pulley and the driven unit is achieved, resulting in a smaller size and a lower weight of the robotic arm and thus improving operative accuracy during the surgeries.

BRIEF DESCRIPTION OF THE DRAWINGS

[0020] To illustrate the technical solutions according to the embodiments of the present disclosure more clearly, the accompanying drawings for describing the embodiments are introduced briefly in the following. It should be appreciated that the accompanying drawings in the following description are only some embodiments of the present disclosure, and those skilled in the art can derive other drawings from the accompanying drawings without creative efforts.

FIG. 1 is a schematic diagram showing a connection between a pulley and a driven unit in the existing technology.

FIG. 2 is a schematic diagram showing a connection between the pulley and a strap in the existing technology.

FIG. 3 is a front view of a pulley according to an embodiment of the present disclosure.

FIG. 4 is a perspective view of the pulley according to an embodiment of the present disclosure.

FIG. 5 is a top view of the pulley according to an embodiment of the present disclosure.

FIG. 6 is a schematic diagram of a structure having a pulley and a driven unit connected with each other according to an embodiment of the present disclosure.

FIG. 7 is a partial view of the structure according to an embodiment of the present disclosure.

FIG. 8 is a partial view of the structure with a strap mounted thereto according to an embodiment of the present disclosure.

FIG. 9 is a partial view of the structure connected to a link of a robotic arm according to an embodiment of the present disclosure.

FIG. 10 is a schematic diagram of a robotic arm having the structure according to an embodiment of the present disclosure.

Reference numerals refer to:

[0021] pulley 100, wheel portion 110, main arc face 111, branch arc face 112, connector chamber 113, circular end surface 114, mounting hole 115, lug portion 120, first end surface 121, first end surface on the left 121-1, first end surface on the right 121-2, second end surface 122, second end surface on the left 122-1, second end surface on the right 122-2, first side surface 123, top surface 124, main connection surface 1241, intermediate connection surface 1242, positioning hole 1243, second side surface 125, driven unit 200, strap 300, strap connector 301, robotic arm housing 400, pulley 110', groove 113', and tabs 120'.

DETAILED DESCRIPTION

[0022] In the following description, several embodiments of the present disclosure are shown by example. It should be appreciated that other embodiments may be derived with changes in mechanical component, structure, electrical, and operation without departing from the spirit and scope of the present disclosure. The following detailed description is not intended to limit the present disclosure, and the scope of embodiments of the present disclosure is limited by the claims.

[0023] All directional indications (such as upper, lower, left, right, front, rear, etc.) in embodiments of the present disclosure are used only to explain relative positional relationships, motion situations, etc., between components under a particular posture (as shown in the drawings), and will change accordingly if the particular posture changes.

[0024] In that present disclosure, expressions concerning "first," "second," etc., are for descriptive purposes only and cannot be understood as indicating or implying their relative importance or implying the number of technical features indicated. Thus, features defined with "first," "second" may explicitly or implicitly include at least one of such features.

[0025] In that present disclosure, unless otherwise specified and defined, the terms "connect," "fix" and the like should be understood broadly, for example, the expression concerning "connect" may be referred to a fixed connection, a detachable connection, or an integral form, may be a mechanical connection or an electrical connection, may be a direct connection or an indirect connection with an intermediate component, may be a communication between interiors of two components or an interaction between two components. For those skilled in the art, the specific meaning of the above terms in the present disclosure may be understood by case.

[0026] In addition, the technical solutions in the various embodiments of the present disclosure may be combined with each other on the basis of practicability for those skilled in the art. The combination which causes conflicts should be considered as nonexistent and does not fall within the protection scope as claimed by the present disclosure.

[0027] The present disclosure aims to provide a pulley and a structure including the pulley connected with a driven unit to resolve the conflict between the minimization of the thickness and maximization of the rigidity of the connection between the end effector and the robotic arm and thus to achieve both a small thickness and a large rigidity.

[0028] As shown in FIGS. 3-5, an embodiment of the present disclosure provides a pulley 100 including a wheel portion 110 and a lug portion 120. The wheel portion 110 is substantially cylindrical and includes two opposite circular end surfaces 114 and a side surface connecting the two circular end surfaces 114. The side surface includes a main arc face 111 and at least one branch arc face 112. The branch arc face 112 has a head end connected to the main arc face 111. In an axial direction of the wheel portion, the branch arc face 112 has a width smaller than that of the main arc face 111, The branch arc face 112 and the main arc face 111 form a continuous circular arc surface. The lug portion 120 is fixed to the wheel portion 110 and is disposed at a position adjacent to the branch arc face 112 along the width of the main arc face 111 and extends to protrude beyond the branch arc face 112 in a radial direction of the wheel portion 110.

[0029] Further referring to FIG. 8, in the pulley 100, the branch arc face 112 further includes a tail end configured to connect a strap 300 which rides on the continuous circular arc surface formed by the branch arc face 112 and the main arc face 111. The lug portion 120 is configured to connect the pulley 100 to a driven unit 200.

[0030] In this embodiment, the main arcuate surface 111 and the branch arc face 112 forms the continuous circular arc surface for wrapping of the strap 300. Compared with the typical pulley which is merely shaped as a wheel, the pulley according to the embodiment of the present disclosure includes, not only the wheel portion 11 which is substantially cylindrical and has the main arcuate surface 111 and the branch arc face 112, but also the lug portion 120 which protrudes from the wheel portion 11 and configured to be fixed to the driven unit. Compared with the existing technology, the present disclosure provides an integrally formed pulley which is simpler in structure, in which the wheel portion 110 is improved for wrapping of the strap 300 and an additional lug portion 120 is provided on the wheel portion 110, the pulley is fixed to the driven unit 200 through the lug portion 120 integrally formed with the wheel portion 110, so that components such as the tabs 120' of the inner lug as shown in FIG. 1 can be omitted. In this way, the thickness of the connection of the pulley 100 is reduced, and a compact structure including the pulley 100 and the driven unit 200 is achieved, resulting in a smaller size and a lower weight of the robotic arm and thus improving operative accuracy during the surgeries.

[0031] In an embodiment, the lug portion 120 includes a first end surface 121 adjacent to and perpendicular to the branch arc face 112, a second end surface 122 opposite to the first end surface 121, a first side surface 123 connecting the first end surface 121 and the second end surface 122 and extending from the main arc face 111, a top surface 124 connecting the first end surface 121 and the second end surface 122 and disposed at a top of the pulley 100, and a second side surface 125 disposed above the branch arc face 112 and connecting the top surface 124. The top surface 124 is, for example, flat and is configured to be attached to a surface (for example, which is also flat) of the driven unit 200, so that the pulley 100 is fixed to the driven unit 200. As an example, the top surface 124 is fixed to the flat surface of a main arm of the driven unit 200 by mechanical connection or welding, or is integrally formed with the main arm of the driven unit 200.

[0032] In this embodiment, with the reasonable design of the lug portion 120, the pulley 100 is connected to the driven unit 200 through the connection of two flat surfaces. While in the existing technology, the connection between the pulley and the driven unit is realized by inserting the pulley between tabs of the driven unit, which may become loose during a long-term operation. The solution provided in the embodiment of the present disclosure avoids such problems during the long-term operation, and thus improves the reliability.

[0033] In an embodiment, a connector chamber 113 is provided at the tail end of the branch arc face 112 and configured to receive and hold a strap connector 301 which is connected to the strap 300. For example, the strap connector 301 is matched in shape with the connector chamber 113. The connector chamber 113 includes an abdomen and a mouth sized smaller than the abdomen, and the mouth opens to the branch arc face 112. In a specific application, the strap connector 301 is received in the connector chamber 113, and the strap 300 extends out of the connector chamber 113 through the mouth and further extends along and rides on the branch arc face 112.

[0034] In this embodiment, the connector chamber 113 with a large abdomen and a small mouth is provided to connect the strap connector 301 without requiring any additional fastener such as screws, which simplifies the connection of the strap connector, and contributes to the reasonable design of the lug portion 120 on the wheel portion 110.

[0035] In an embodiment, the mouth of the connector chamber 113 has a top connecting the second side surface 125, and the top surface 124 is disposed above the connector chamber 113 and spaced from the connector chamber 113. In this way, with such a simple structure, it is effectively ensured that no interference occurs between the strap connector and the robotic arm or the driven unit 200 during operation.

[0036] In an embodiment, the pulley 100 is rotated-symmetrical about the radial direction of the wheel portion 110 (i.e., the broken line L as shown in FIG. 3). Each of the left and right sides of the pulley 100 includes a branch arc face 112, a connector chamber 113 and a lug portion 120, so that the two straps 300 are connected to the pulley and run in opposite directions. Specifically, the first end surfaces 121 (i.e., a first end surface 121-1 on the left and a first end surface 121-2 on the right as shown in FIG. 4), the second end surfaces 122 (i.e., a second end surface 122-1 on the left and a second end surface 122-2 on the right as shown in FIG. 4) and the second side surfaces 125 (not indicated with separate reference numerals) of the two lug portions 120 are also rotated-symmetrical. The rotated-symmetrical structure makes it possible to connect the straps 300 at both sides, and contributes to force balancing.

[0037] In an embodiment, each of the two branch arc faces 112 has a central angle larger than 90°, so that the pulley 100 is driven by the straps 300 to rotate both clockwise and anticlockwise by over 90°. In an embodiment, the main arc face111 has a central angle of 180°. The width of each of the two branch arc faces 112 is half that of the main arc face 111. The two branch arc faces 112 partly overlap in the axial direction of the wheel portion 110 and share the main arc face 111. In this way, the wheel portion 110 has a simple structure. In an embodiment, the first side surface 123 of the lug portion 120 transitions smoothly to the main arc face 111 and extends in a direction away from the main arc face 111 to be lifted from a plane that is tangent to the main arc face 111 at the connection between the main arc face 111 and the first side surface 123. In this way, the pulley 100 has a smooth outline, and the connection area between the pulley 100 and the driven unit 200 is increased. In an embodiment, the top surface 124 includes a main connection surface 1241 on each side and an intermediate connection surface 1242 connecting the main connection surfaces 1241. In an embodiment, a wiring hole 1243 is provided and opens at the top surface 124 for allowing wires to pass therethrough and enter the driven unit 200. In an embodiment, the wheel portion 110 defines a mounting hole 115 penetrating through the two circular end surfaces in the axial direction of the wheel portion 110. The mounting hole 115 allows a rotary shaft of the robotic arm to be inserted therein.

[0038] In the above embodiments, with cooperation of the lug portion 120 and the connector, the pulley 100 can achieve the connection between the connector and the lug portion 120 and the normal wrapping of the strap, and the driven unit 200 is rotatable by a large angle with driven of the pulley 100. Meanwhile, the thickness of the robotic arm is reduced and the rigidity of the connection between the robotic arm and the end effector is increased. Further, no interference with the robotic arm occurs in the subsequent installation.

[0039] As shown in FIGS. 6-10, an embodiment of the present disclosure provides a structure including a pulley and a driven unit connected to each other. The pulley 100 is connected to the driven unit 200 through the lug portion 120. For example, the lug portion 120 is fixed to the driven unit 200 by mechanical connection or welding, or is integrally formed with the driven unit 200. For example, the top surface 124 of the lug portion 120 is attached to a flat surface of the driven unit 200. The driven unit 200 may be an end effector for a robotic arm, particularly an end instrument holder of a surgical robot. The strap connector 301 at the end of the strap 300 is held in the connector chamber 113 below the top surface 124, and the second side surface 125 provides a safe distance for avoiding interference between the strap connector and the driven unit 200. The pulley 100 is fixed to the driven unit 200 as shown in FIGS. 6 and 7, and then the strap connector 301 is inserted into the connector chamber 113 as shown in FIG. 8, and then a rotary shaft is inserted into the mounting hole 115, and the pulley 100 is sandwiched by the robotic arm housing 400, as shown in FIG. 9. As shown in FIG. 10, an embodiment of the present disclosure provides a robotic arm having the structure. The robotic arm may be used in a surgical robot.

[0040] In this structure, the connection of the driven unit 200 and the pulley 100 are "half-connected," that is, two straps 300 each wraps about a half of the pulley 100 on the left side or right side, and the lug portion 120 without strap 300 wrapping thereon is connected to the driven unit 200. In this way, the thickness of the connection is greatly reduced as the tabs of the end effector used in the existing surgical robot is omitted, resulting in a reduced thickness of the end link of the robotic arm and a compact connection with higher rigidity.

[0041] In FIG. 7, the pulley is rotated-symmetrical about the radial direction of the wheel portion 110 with being hollowed at the front upper left and the rear upper right, or at the front upper right and the rear upper left. The straps 300 are connected to the lug portion and extend to ride on the wheel portion within the hollows. In this way, the thickness of the link of the robotic arm is greatly reduced. The rigidity of connection is increased as the connection area between the lug portions and the end effector.

[0042] In an embodiment, the strap 300 may include a steel strap, or other flexible transmission mechanisms such as belts, ropes, or the like. During running of the strap, the pulley rotates by less than a round. The lug portion for connection with the driven unit is disposed at a same level in the width of the pulley as the strap, resulting an improved efficiency in space utilization. Those having the same concept as the present disclosure are considered as variants to the embodiments of the present disclosure.

[0043] Compared with the related art, in the pulley 100 and the structure including the pulley 100 and the driven unit 200 connected to each other according to the embodiments of the present disclosure, a integrally formed pulley is provided with a simpler structure, in which the wheel portion 110 is improved for wrapping of the strap 300 and an additional lug portion 120 is provided on the wheel portion 110, the pulley 100 is fixed to the driven unit 200 through the lug portion 120 integrally formed with the wheel portion 110, so that components such as the tabs 120' of the inner lug as shown in FIG. 1 can be omitted. In this way, the thickness of the connection of the pulley 100 is reduced, and a compact structure including the pulley 100 and the driven unit 200 is achieved, resulting in a smaller size and a lower weight of the robotic arm and thus improving operative accuracy during the surgeries.

[0044] The description above is merely some embodiments of the present disclosure, and is not intended to limit the scope of the present disclosure. Any equivalent structural transformation made using the contents of the specification and drawings of the present disclosure or applied in other related technical fields under the concept of the present disclosure falls within the scope of the present disclosure.

Claims

1. A pulley comprising:

a wheel portion including two circular end surfaces opposing each other and a side surface connecting the two end surfaces, wherein the side surface includes a main arc face and a branch arc face, the branch arc face has a head end connected to the main arc face and a tail end configured to connect a strap, the branch arc face has a width in an axial direction of the wheel portion smaller than a width of the main arc face, and the branch arc face and the main arc face form a continuous circular arc surface on which the strap rides; and

a lug portion fixed to the wheel portion, wherein the lug portion is disposed at a position adjacent to the branch arc face along the width of the main arc face and extends to protrude beyond the branch arc face in a radial direction of the wheel portion, and the lug portion is configured to connect the pulley to a driven unit.

2. The pulley according to claim 1, wherein the lug portion includes a first end surface adjacent to and perpendicular to the branch arc face, a second end surface opposite to the first end surface, a first side surface connecting the first end surface and the second end surface and extending from the main arc face, a top surface connecting the first end surface and the second end surface and disposed at a top of the pulley, and a second side surface disposed above the branch arc face and connecting the top surface, and the top surface is configured to be attached to a surface of the driven unit.

3. The pulley according to claim 2, wherein a connector chamber is provided at the tail end of the branch arc face and configured to receive and hold a strap connector which is connected to the strap and matched in shape with the connector chamber.

4. The pulley according to claim 3, wherein the connector chamber includes an abdomen and a mouth sized smaller than the abdomen, and the mouth opens to the branch arc face.

5. The pulley according to claim 4, wherein the mouth has a top connecting the second side surface, and the top surface is disposed above the connector chamber and spaced from the connector chamber.

6. The pulley according to any one of claims 1 to 5, wherein two branch arc faces and two lug portions are provided, and the pulley is rotated-symmetrical about the radial direction of the wheel portion.

7. The pulley according to claim 6, wherein each of the two branch arc faces has a central angle larger than 90°.

8. The pulley according to claim 7, wherein the main arc face has a central angle of 180°, the width of each of the two branch arc faces is half that of the main arc face, the two branch arc faces partly overlap in the axial direction of the wheel portion and share the main arc face.

9. The pulley according to claim 2, wherein the first side surface of the lug portion transitions smoothly to the main arc face.

10. A structure including a driven unit and a pulley according to any one of claims 1 to 9 connected to the driven unit through the lug portion.

11. The structure according to claim 10, wherein the driven unit is an end effector for a robotic arm.

Drawing